Disc Break stopping power.

I was under the assumption Disc breaks provided very strong and firm stopping power, though today testing a few bikes at a LBS I was less then impressed. In fact I found both mechanical or hydrolic disc breaks to be pretty weak compared to normal V Breaks. am I missing something?

As a new set of disc brakes gets used, a small amount of pad material is deposited onto the rotor. This improves power greatly. As mentioned above, this break-in period applies to both bike and car brakes.

Discs provide a lot of power, as much or more than v-brakes. But where they really improve on v's is how little finger effort is needed for the same power. Lever feel and modulation are typically better too. And of course, they're better in adverse weather and stream crossings.

I was under the assumption disc brakes provided very strong and firm stopping power, though today testing a few bikes at a LBS I was less then impressed. In fact I found both mechanical or hydraulic disc brakes to be pretty weak compared to normal V brakes. Am I missing something?

You didn't ride broken-in disc brakes. What you're missing is that, yes, discs are more powerful than vees but they require a bit of riding to be fully broken-in, as opposed to vees which grab their best right away. I know, I have a vee brake bike and three disc brake bikes. Discs are more powerful, hands down. Vees do stop me, though, can't complain.

A blind man searches in a dark room for a black hat that isn't there. Dashiell Hammett

I think what you are experiencing is better modulation with discs, don't skid as quick and give you better feel, and brand new brake pads. Trust me, when you need brakes, they'll be there. My old V Brakes were completely useless after 100 yards of good steep downhill.

Doing a couple 10mph parking lot stops won't show what the disks are capable of. They are worlds apart when you're going downhill at 40mph and have power and modulation to spare with one finger on the lever.